Snaring systems and methods

ABSTRACT

Snaring systems and methods involve engaging objects such as pacemaker pacing leads within a patient. Physicians can use snaring systems having loops, tags, and roller mechanisms to remove a pacing leads from a patient. For example, snaring systems can be inserted through a jugular access site, engaged with a pacemaker pacing lead, and withdrawn through the jugular access site so as to remove a portion of the pacing lead. Lead extraction techniques can be employed to further dislodge the pacing lead from the patient.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/878,648, filed Sep. 9, 2010, which is a nonprovisional of and claimsthe benefit of priority to U.S. Provisional Patent Application No.61/242,225 filed Sep. 14, 2009. The contents of each of the aboveapplications are incorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION

Embodiments of the present application relate generally to systems andmethods for separating or removing an object from a patient, and morespecifically, to techniques for grasping pacing leads within a patient.

A pacemaker can be used to improve heart function in a patient. Forexample, a pacemaker can transmit electrical signals to the patient'sheart, so as to assist the heart to beat in a desired heart rhythm. Apacing system typically includes a pacemaker, a pacing lead, and acontroller or processer. A pacing lead often has a wire that transmitselectrical impulses to cardiac tissue. Optionally, a pacing lead maytransmit information regarding cardiac activity to the pacemaker orprocessor.

In certain situations, it may be desirable or necessary to remove apacing lead from a patient. For example, a patient may develop aninfection in tissue which is contacting the pacing lead or pacemaker. Itmay also be advantageous to remove the lead or lead fragment if the leadbreaks or otherwise poses a risk of damage, discomfort, or obstructionor interference, if the lead interferes with the operation of anotherimplanted device, or if the patient's vasculature or tissue which islocated at or near the lead becomes obliterated or occluded.

In some cases, a lead may develop or present a free end, which can occurwhen a lead breaks, is pulled out of a header, or is otherwise abandonedduring a surgical intervention. If a lead has a free end, it istypically located in the brachiocephalic vein. To remove a lead having afree end, it may be desirable for the physician or operator to navigatethe free end of the lead toward an incision site.

Several lead grasping and removal techniques have been proposed.However, some approaches may not be well suited for easily accessing,grasping, or manipulating the free end of a lead. For example, some pigtail catheters may have a limited holding capability, and the lead mayslip out of the catheter before it is freed from the patient's anatomy.In certain instances, pig tail catheters can tend to straighten out whenpulled by the operator, thus disengaging the lead from the pig tail.Some snares grasp the lead with inappropriate levels of force. Hence,there continues to be a need for improved systems and methods that cansimply and effectively grasp and remove a pacing lead or other objectfrom a patient in a reliable manner.

Although some currently proposed treatments may provide real benefits topatients in need thereof, still further advances would be desirable.Embodiments of the present invention provide or intravascular hook orsnaring solutions that address the problems which may be associated withthe techniques described above, and hence provide answers to at leastsome of these outstanding needs.

BRIEF SUMMARY OF THE INVENTION

Grasping snares and method for grasping a pacing lead and removing itfrom the body are disclosed herein. For example, an operator may advancea snaring system through a jugular access site in a patient, providing arelatively non-tortuous pathway to the superior vena cava where thesnaring system can be engaged with a pacing lead. Using the snaringsystem, it is possible to maneuver the pacing lead, which optionally mayinvolve pulling the lead so as to disengage a proximal portion or adistal portion of the lead from an attachment site within the patient.Once a distal or proximal portion of the pacing lead is disengaged, thephysician can maneuver the free end toward the access site, by looselyengaging the snaring system with the pacing lead. In some cases, thismay involve the use of a snaring system having one or more rollerbearings or sleeves. The snaring system can be translated along a lengthof the pacing lead, and can be used to maneuver or pull a free end ofthe pacing lead, without transmitting an excessive amount of pullingforce or stress on the opposing secured end of the pacing lead.

Advantageously, such grasping snares may be operated with significantpulling forces, while maintaining an engagement with a pacing lead.Exemplary snaring systems include a snare wire with a hooked distal endthat is slidable within the wall or lumen of an outer sheath or jacket.Such arrangements permit the distal end of the snare wire to be moveddistally away from the outer jacket in order to snare the pacing lead.Once grasped, the pacing lead can be pulled back into the inner lumen ofthe outer jacket so that it can be withdrawn from the body. Embodimentsof the present invention also encompass deflection tendons or bendingwires that can be incorporated into the outer jacket to bend or deflectthe distal tip of the outer jacket. Embodiments may also include snareshaving a closed hook at their distal end. A distal end or snare hook mayhave one or more rotatable bearings. In use, a snare can be insertedinto the jugular vein of a patient. The snare can be used to grasp orengage the pacing lead and pull one end out through the jugular veinaccess site. Once the lead end is extending outside the body, typicallead extraction techniques can be employed. In some cases, graspingsnare wires can be extended or advanced through a wall of a catheterbody.

Relatedly, embodiments of the present invention encompass systems andmethods for snaring or grasping a lead which is disposed within ananatomical location of the patient, such as the jugular vein, thesuperior vena cava, the right atrium, the right ventricle, thebrachiocephalic vein, or the like. Advantageously, the techniquesdisclosed herein allow a surgeon or operator to effectively grasp, push,pull, twist, rotate, or otherwise maneuver or manipulate an object, suchas a pacing lead, within the patient. What is more, snaring systemsdisclosed herein can withstand high pulling forces without releasing apacing lead, and can effectively snare a lead in a midsection or centralportion, without being threaded over the end of the pacing lead.Exemplary snaring systems allow a pacing lead to slide through a distalhook of a snare wire, without imparting high forces to the pacing leador adhered vasculature. Features such as a hook tag end and a bent orshaped snare wire allow an operator to effectively steer or navigate thesnare system to the pacing lead for capture. Moreover, snaring systemsdisclosed herein are easily releasable from the pacing lead. In somecases, snaring systems can include a hook or snare that can hook andretain a pacing lead, and pull a portion of the pacing lead downwardtoward the femoral vein or upward toward the jugular vein and out of theaccess site. Systems can also allow the pacing lead to move through asnare wire or catch mechanism as the lead is being pulled or during thesnaring process. Exemplary embodiments can also release a hook or snareif the procedure is not successful or is interrupted.

In one aspect, embodiments of the present invention encompass snaringsystems and methods for engaging an object within a patient's body. Anexemplary snaring system includes an elongate element having a proximalend and a distal end. The distal end can include a loop. The system alsoincludes an outer sheath having a central lumen. The central lumen canbe configured to receive at least a portion of the loop of the distalend of the elongate element. In some cases, a system may also include arotatable bearing in operative association with the loop of the distalend of the elongate element. The distal end of the elongate element caninclude a tag, and the central lumen of the outer sheath can beconfigured to receive the tag. In some embodiments, the outer sheathincludes a second lumen extending through a side wall of the sheath, andthe second lumen is configured to receive at least a portion of theelongate element.

In some cases, the elongate element includes a flattened portion, asquare cross section portion, or a rectangular cross section portion.Optionally, the system may include a deflection mechanism coupled withthe outer sheath.

In another aspect, embodiments of the present invention encompasssystems and methods for engaging a pacing lead disposed within apatient. An exemplary method includes inserting a snaring system througha jugular or femoral access site of a patient, engaging a pacing leadwith the snaring system, sliding the snaring system along a length ofthe pacing lead so as to move a portion of the pacing lead toward thejugular or femoral access site of the patient, and withdrawing thesnaring system from the jugular or femoral access site so as to removeat least a portion of the pacing lead from the patient. In some cases,the step of engaging the pacing lead can include engaging the pacinglead with a roller mechanism of the snaring system. In some cases, thestep of engaging the pacing lead can include engaging the pacing leadwith a capture mechanism of the snaring system. Optionally, the capturemechanism of the snaring system can include an elongate element having aloop. In some cases, the step of engaging the pacing lead can includesliding the elongate element along a side wall lumen of a catheter ofthe snaring system.

In a further aspect, embodiments of the present invention encompasssystems and methods for engaging an object disposed within a patient. Anexemplary method may include inserting a snaring system through anaccess site of a patient. The snaring system can include an elongateelement having a distal loop and a rotatable roller mechanism disposedalong the distal loop of the elongate element. The method may alsoinclude engaging the object with rotatable roller mechanism of thesnaring system, and withdrawing the snaring system toward the accesssite so as to move at least a portion of the object toward the accesssite. In some cases, the elongate element may include a tag end that isdisposed distal to the rotatable roller mechanism. The rotatable rollermechanism may include a bearing having a tubular shape. Optionally, therotatable roller mechanism may include a bearing having a sphericalshape. In some cases, the rotatable roller mechanism includes a firstcylindrical bearing defining a first central longitudinal axis and asecond cylindrical bearing defining a second central longitudinal axis.The first central longitudinal axis can be angularly offset from thesecond central longitudinal axis. In some instances, the first centrallongitudinal axis is angularly offset from the second centrallongitudinal axis by about 90 degrees.

In still another aspect, embodiments of the present invention encompassa snaring system for engaging an object within a patient's body, whichincludes an elongate element having a proximal end and a distal end. Thedistal end of the elongate element can include a loop and a tag. Thesnaring system may also include a rotatable bearing in operativeassociation with the loop of the distal end of the elongate element. Insome cases, the rotatable bearing is disposed on a first section of theloop, and the loop has a second section distal to the first section anda third section proximal to the first section, such that the secondsection and the third section are in substantial parallel alignment. Insome cases, the first section is in substantial perpendicular alignmentwith each of the second section and the third sections.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be had to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1F illustrates aspects of object grasping or removal systemsand methods according to embodiments of the present invention.

FIG. 2 illustrates aspects of an object removal system or grasping snareaccording to embodiments of the present invention.

FIGS. 3A to 3D illustrate aspects of an object removal system orgrasping snare according to embodiments of the present invention.

FIGS. 4A and 4B illustrate aspects of a grasping snare system accordingto embodiments of the present invention.

FIGS. 5A and 5B illustrate aspects of a grasping snare system accordingto embodiments of the present invention.

FIG. 6 illustrates aspects of an object removal or snaring systemaccording to embodiments of the present invention.

FIGS. 7A and 7B illustrates aspects of pacing lead snaring or removalsystems and methods according to embodiments of the present invention.

FIG. 8 depicts aspects of a snaring system according to embodiments ofthe present invention.

FIG. 9 depicts aspects of a snaring system according to embodiments ofthe present invention.

FIG. 10 depicts aspects of a snaring system according to embodiments ofthe present invention.

FIGS. 11 to 11C depict aspects of a snaring system according toembodiments of the present invention.

FIGS. 12A to 12C depict aspects of a snaring system according toembodiments of the present invention.

FIGS. 13A and 13B depict aspects of a snaring system according toembodiments of the present invention.

FIGS. 14A and 14B depict aspects of a snaring system according toembodiments of the present invention.

FIGS. 15 to 15C depict aspects of a snaring system according toembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In certain surgical situations, a patient may present with a pacing leadthat is no longer disposed within the pocket, but instead is freelyfloating in the brachiocephalic vein, the superior vena cava, the rightatrium, or the like. Embodiments of the present invention providetechniques for grasping a free end of the pacing lead and maneuvering orpulling it toward the jugular vein. Exemplary approaches provide removalor snare systems that can hook, grasp, push, pull, and twist a pacinglead. Such advances allow an operator may degrees of freedom whenremoving a lead having a free end.

According to embodiments of the present invention, techniques mayinclude pulling the free end of the lead down from the femoral veinusing a femoral vein approach. Once the lead is located within the rightatrium or inferior vena cava, the physician can use a snare deviceinserted through the jugular vein to grasp or engage the lead and pullit toward an opening or incision in the jugular vein. The free end ofthe lead can be pulled back up through the jugular vein, via theinferior vena cava, right atrium, and superior vena cava. In some cases,this technique can involve using a first snare to hook the lead and pullthe lead down through the inferior vena cava and into the femoral vein.The technique can also involve using a second snare to grasp or engagethe end of the lead from a jugular access site, and pull the free end upthrough the jugular access site. Optionally, a laser sheath or otherremoval device can then be used over the lead to free or dislodge thedistal end of the lead for removal.

Turning now to the drawings, FIGS. 1A to 1F illustrates aspects of anobject grasping or removal system 100 according to embodiments of thepresent invention. FIG. 1A shows a pacing lead 10 disposed within apatient's body, such that a free end 12 of the lead is floating freelywithin the brachiocephalic vein. As depicted in FIG. 1B, an objectgrasping or removal system 100 can be advanced within the jugular vein,and then used to snare, grasp, hook, or otherwise engage the pacinglead. In some cases, grasping or removal system 100 is used to grasp orengage pacing lead 10 at or near a central portion 14 of the pacinglead. Optionally, grasping or removal system 100 can be used to grasp orengage a portion of pacing lead 10 which is disposed at or near theright atrium, or at or near the superior vena cava. As shown here,object grasping or removal system 100 includes an outer sheath 110 and acatch mechanism 120. The catch mechanism is extended from the outersheath, so that it may contact, hook, or engage the pacing lead.

As illustrated in FIG. 1C, catch mechanism 120 can be activated, forexample by withdrawing it into outer sheath 110, so as to capture,secure, or engage the pacing lead. While pacing lead 10 is engaged orfirmly held by grasping or removal system 100, the operator maymanipulate the removal system so as maneuver the pacing lead as desired.In some cases, it may be desirable or beneficial for the physician toadminister a pulling action, wherein the pacing lead is not firmlygrasped by the snaring system, but instead is more loosely engaged bythe snaring system, such that he snaring system allows movement of thepacing lead through a snaring loop of the system during withdrawal ofthe lead. As shown in FIG. 1C, the operator can push grasping or removalsystem 100 into or toward the right atrium, in the direction illustratedby arrow A, thus advancing the pacing lead into or toward the rightatrium. Subsequently, free end 12 of pacing lead 10 is withdrawn fromthe brachiocephalic vein and into or near the right atrium, asillustrated in FIG. 1D. Although FIG. 1D illustrates the situation wherea proximal portion of the pacing lead becomes freed, embodiments of thepresent invention also encompass situations where instead, or inaddition, a distal portion of the pacing lead becomes freed. Forexample, when physician uses the snaring system to pull on the pacinglead, the distal end of the pacing lead may become dislodged orseparated from the cardiac tissue.

The surgeon may adjust the positioning of the object grasping or removalsystem on the pacing lead. For example, as shown in FIG. 1E, catchmechanism 120 can be released or relaxed, for example by extending itfrom outer sheath 110. Hence, the catch mechanism is in an openconfiguration, and the grasping or object removal system can berepositioned as desired at another location along the pacing lead. Inthe embodiment shown here, grasping or object removal system isrepositioned toward free end 12 of pacing lead 10. In some cases, theoperator may slide the grasping or removal system along the pacing leadto achieve the desired repositioning.

When the grasping or removal system is in the appropriate locationrelative to the pacing lead, the operator may activate catch mechanism120 so as to firmly secure or grasp pacing lead 10 with removal system100, as shown in FIG. 1F. The operator may then pull or withdraw thepacing lead through the jugular vein, and toward a jugular access site,in direction indicated by arrow A. The operator may then use the jugularaccess site to pass a laser sheath or other lead removal device alonggrasping or removal system 100.

As shown in FIG. 2, an object removal system or grasping snare 200 caninclude an outer sheath 210 such as a jacket or tube, and a catchmechanism 220 such as an snare wire. In some cases, catch mechanism 220includes an internal wire having a distal hook. The internal wire canrun along a length of the tube, and the wire can be configured to moveaxially within the tube. For example, in some cases the wire can slidealong an inner wire lumen 212 of the tube. The distal end 222 of thewire 220 which includes the hook can also be received or disposed withina catch lumen 214 of the tube. For example, in some cases the distalhook can be extended from a distal portion 216 of the tube, andretracted back toward or into the tube. The wire can have a proximal end224, which extends from a proximal portion 218 of tube 210, thatincludes a loop or pull mechanism 226 such as a pull or torque handle.Outer jacket or tube 210 can be used by the operator to support or carrysnare wire 220, and to provide push, pull, and rotation movements.

In operation, the physician can use the distal hook of the wire, forexample when it is extended from the tube, to grasp or snare the freelead. For example, FIG. 3A illustrates an object removal system orgrasping snare 300 having an outer tube 310 and a snare wire 320. Thecatch mechanism or snare wire 320 is in an open position. FIG. 3B alsoshows snare wire 320 in an open position, wherein the snare wire isrotated about 180 degrees relative to the configuration shown in FIG.3A. A distal hook 322 can assist in functioning as a grasping snare or ahook snare. When a pacing lead 330 is disposed within hook 322, theoperator can pull the snare wire toward the outer tube, as shown in theclosing position or configuration depicted in FIG. 3C. When the pacinglead is engaged with or corralled by the hook, the hook can be movedalong a length of the pacing lead, or the hook can be used to maneuverthe positioning of the pacing lead, without applying a significantpulling or pushing force to the pacing lead, or to an affixed orembedded portion of the pacing lead. What is more, the operator can pullsnare wire 320 further into tube 310, thus firmly grasping the lead, asshown in the closed position or configuration depicted in FIG. 3D. Thegrasping snare 300 can then be used to push, pull, twist, or otherwisemaneuver pacing lead 330. To release the lead, the operator can extendthe distal hook of the wire from the tube, for example by pushing itforward relative to the tube, thus exposing the hook.

As illustrated in the embodiment depicted in FIG. 4A, grasping snaresystem 400 can include an outer tube 410 and an inner snare wire 420.Snare wire 420 can be rotated relative to tube 410 as indicated by arrowA, optionally via rotation of a wire handle 426 as indicated by arrow Ashown in FIG. 4B. Relatedly, snare wire 420 can be translated relativeto tube 410 as indicated by arrow B shown in FIG. 4A, optionally viatranslation of wire handle 426 as indicated by arrow B shown in FIG. 4B.In some cases, snare system 400 can include a seal disposed toward aproximal end of tube 410, or a luer fitting that accepts a rotatinghemostasis valve.

As shown in FIG. 4A, tube or outer jacket 410 of snare system 400 mayhave two lumens, for example a wire lumen 412 and a capture lumen 414.According to some embodiments, wire lumen 412 can be laterally offsetfrom a central longitudinal axis 416 of the outer jacket. For example,wire lumen 412 can be disposed within a wa11418 of jacket 410. Accordingto such configurations, snare wire 420 can be constrained to orcontained within one side of the tube. Such tube configuration can alsoallow a distal hook 422 of the wire to be rotated outside the axis orsilhouette defined by the outer diameter 419 of the tube, so as toprovide a larger snaring area. Wire lumen 412 within the tube canpresent a slot configuration. For example, as shown in FIG. 5A, wirelumen 512 a can present an oval shaped cross section. Relatedly, asshown in FIG. 5B, wire lumen 512 b can present a square or rectangularshaped cross section.

Such shaped inner wire lumens 512 a, 512 b can be formed during anextrusion process, or reformed with an insert. Relatedly, the snare wirecan include a shaped portion, which presents a similarly shaped ovularor rectangular profile. For example, as depicted in FIG. 4A, it ispossible to provide a flattened portion 423 at or near the distal curvesection 422 of the snare wire 420 to key it into the lumen or slot 412in the side or wall of outer jacket 410. In this way, snare wire 420 canbe keyed with tube 410. Such modifications can increase the surface areaon the outer or top portion of the loop 422 to prevent or inhibit snarewire 420 from cutting into or stripping the pacing lead. Hence, aflattened or shaped portion can be placed on the distal section of thewire to key the snare wire to the tube. A section of the wire proximalto the flattened or shaped portion can be round or rounded in shape, soas to allow the snare wire to be rotated relative to the tube within theinner wire aperture, when the flattened or shaped section is distal tothe tube lumen. In addition to flattened shapes, the snare wire and slot412 may present square cross-section shapes, rectangular cross-sectionshapes, and other complementary interlocking or keyed shapes. In someembodiments, such keyed snaring systems may include roller bearings orsleeves as described elsewhere herein, for example with reference toFIGS. 9 to 11C, and 15 to 15C.

According to some embodiments, snare wire 420 or loop area 422 caninclude a slip coating or reduced friction surface, to allow the snareto slide along the lead, for example when the snare is being opened orclosed. In some cases, such a coating or surface can include PTFE,Teflon, Teflon spray, paralene, or any suitable reduced-friction spray,tubing, coating, or solution.

Outer jacket or tube 410 can be constructed of one or materialsincluding Pebax, ABS, PEEK, FEP, PE, Nylon, a Pebax braid matrix, or thelike. The outer diameter (OD) of the tube can be within a range fromabout 0.090 inches to about 0.160 inches. In some cases, the outerdiameter of the tube can be sized so as to allow a laser sheath, whichmay be 12Fr to 16Fr, to pass over the snaring assembly. For example, theouter diameter can be sized to allow a 12Fr laser sheath pass over thetube 410. The snare wire can be constructed of one or more materialssuch as stainless steel, NiTi, or the like. The outer diameter (OD) ofthe wire can be within a range from about 0.010 inches to about 0.050inches. The wire can be configured to provide sufficient strength topull on a pacing lead while providing sufficient flexibility to navigatethe patient's anatomy.

As shown in FIG. 6, embodiments of the present invention encompassmechanisms that can deflect a distal end of the outer tube. Snaringsystem 600 includes an outer tube 610, a snare wire or capture mechanism620, and a deflection mechanism 650. The deflection mechanism mayinclude, for example, a pull wire or a steering tendon 660. Deflectionmechanism 650 can provide to the snare system an additional degree offreedom while manipulating the snare system to grasp a pacing lead. Insome cases, a deflection mechanism can include a tendon wire that ishoused in a wall of outer tube 610, for example within a deflectionmechanism lumen 616, and anchored at some point distal, for example atan anchor point 618. According to some embodiments, the location ofanchor point 618 along the length of tube 610 can be determined by theradius of curvature desired during operation of the deflectionmechanism. For example, as the anchor point is located more closely to adistal end 619 of tube 610, it is possible to achieve a bend in tube 610having a smaller radius of curvature when actuating the deflectionmechanism. According to some embodiments, anchor point 618 can belocated within 20 cm of the distal end of tube 610. In some cases,anchor point 618 may include an embedded eyelet or an anchor band.Anchor point 618 can serve to fix a distal portion of the pull wirerelative to the outer tube.

As depicted in FIG. 6, deflection can be effected by applying tension toa proximal end 652 of the tendon wire, for example by pulling the wirein the direction indicated by arrow A, which in tum causes the distalend of the tube to deflect in the direction indicated by arrow B. Thetendon wire can have a diameter within a range from about 0.005 inchesto about 0.030 inches, according to some embodiments. The tension can beapplied by through the use of a mechanical mechanism or through the useof manual force provided directly by the user. In some cases, amechanical deflection mechanism can include a screw, a cam orcylindrical disk, a lever, or other mechanical means to tension a wire.A mechanical deflection mechanism could be mounted in a housing tocreate a handle. According to some embodiments, a handle can beconfigured to lock the tube in a deflected configuration as desiredduring a surgical procedure, and until the operator unlocked the tubefrom the deflected orientation.

According to some embodiments, a snare system may include a pre-shapedouter tube that can be straightened or shaped by advancing a straight orshaped mandrel through a lumen in the wall of the outer tube. The degreeof straightening, or deflection, can be controlled by the distance orextent to which the mandrel is advanced distally into the wall or lumenof the outer tube. In some cases, a mandrel can be integrated with theouter tube, yet allow it to be slidable. In some cases, a mandrel can bean auxiliary member that is removable. A distal end of the mandrel canbe made with a ball-end tip to prevent or inhibit it from perforatingthe outer tube when it is advanced.

Snaring systems which include shaped wire element such as those depictedin FIGS. 2, 3A to 3D, 4A, and 6 are well suited for loosely engaging andmaneuvering a pacing lead without subjecting the pacing lead tosignificant pulling forces. Such systems are particularly useful inpacing lead removal methods such as those described herein withreference to FIGS. 7A and 7B. For example, in some cases, it may bedesirable or beneficial for the physician to administer a pullingaction, wherein the pacing lead is not firmly grasped by the snaringsystem, but instead is more loosely engaged by the snaring system, suchthat the snaring system allows movement of the pacing lead through asnaring loop of the system as the system is navigated or manipulated bythe physician.

As noted above, exemplary lead extraction procedures can involve afemoral or jugular approach to accessing or removing the lead, incontrast to a superior or lead pocket approach. FIG. 7A illustratesaspects of a lead snaring or removal process, according to embodimentsof the present invention. As depicted here, pacing lead 701 is disposedwithin the patient, such that a distal portion 702 of pacing lead 701 issecured in the patient's right ventricle. A proximal portion 703 ofpacing lead is disposed at or near the pacemaker pocket of the patient.Snaring system 710 can be used to snare, grasp, or otherwise engage thepacing lead. For example, an elongate element or hooked wire of thesnaring system can be inserted into the vasculature through a snaringsystem sheath, either from a jugular vein or femoral vein access site.The distal hook or loop can be placed near the pacing lead at or nearthe vicinity of the superior vena cava. A distal loop 712 of snaringsystem 710 can be used to hook a central portion 704 of the pacing lead,optionally by maneuvering or manipulating a control handle 714 of thesnaring system. For example, the snaring wire can be rotated via ahandle or pin vice 714 so that a hook tag end of distal portion 712catches the lead. The operator can pull up on the snare wire or snaringsystem to cause the pacing lead to slide into the enclosed area of thedistal hook.

As shown in FIG. 7B, when the distal loop or hook 712 of snaring system710 has caught the pacing lead, the snaring system can be retracted orpulled up in the direction indicated by arrow A, so as to withdrawproximal portion 703 of the pacing lead away from the pacemaker pocket,and into the jugular vein. During withdrawal of the snaring system,distal loop 712 of the snaring system can slide along a length of thepacing lead, from central portion 704 toward proximal portion 703, asindicated by arrow B. Although FIGS. 7A and 7B illustrate the situationwhere a proximal portion of the pacing lead becomes freed, embodimentsof the present invention also encompass situations where instead, or inaddition, a distal portion of the pacing lead becomes freed. Forexample, when physician uses the snaring system to pull on the pacinglead, the distal end of the pacing lead may become dislodged orseparated from the cardiac tissue.

Optionally, as discussed elsewhere herein, a sheath can be placed overthe snaring wire and advanced over the tag end of the distal hook, so asto cinch or secure the pacing lead to the snaring system. The sheath andsnaring wire can then be pulled to free the proximal portion of thepacing lead. Once free, the snaring wire and sheath can be pulled out ofthe body access site along with the proximal end of the pacing lead.With the proximal end of the pacing lead disposed outside of the body,the entire pacing lead can be extracted via lead extraction techniques,for example via laser lead extraction. To disengage the snaring systemfrom the pacing lead, the operator can push and rotate the snaring wireto release the hook from the pacing lead.

FIG. 8 depicts a snaring system 800 according to embodiments of thepresent invention. Snaring system 800 includes an elongate element orwire 810 having a proximal portion 812 and a distal portion 814. System800 can include a pin vice or handle 820 coupled with proximal portion812 of elongate element 810. As shown here, distal portion 814 ofelongate element 810 includes a looped or hooked portion 815. Distalportion 814 can also include a tag end 816. According to someembodiments, elongate element 810 includes a stainless steel wire havinga diameter of about 0.020 inches. Looped portion 815 can have a length Lof about 0.5 inches and a width W of about 0.2 inches. In some cases,tag end 816 can have a length LT of about 0.25 inches. In some cases,tag end 816 can have a length LT of about 0.50 inches.

FIG. 9 depicts a snaring system 900 according to embodiments of thepresent invention. Snaring system 900 includes an elongate element orwire 910 having a proximal portion 912 and a distal portion 914. System900 can include a handle 920 coupled with proximal portion 912 ofelongate element 910. As shown here, distal portion 914 of elongateelement 910 includes a looped or hooked portion 915. Distal portion 914can also include a tag end 916. System 900 further includes a bearing orsleeve 919 disposed about a section of distal portion 914. In somecases, bearing 919 can rotate about elongate element 910. Bearing 919can provide reduced friction between elongate element 910 and a pacinglead. Elongate element 910 can include one or more bends 911 which canenhance steerability of the snaring system. A bearing element caninclude a metal material, such as stainless steel, titanium, or thelike. In some cases, a bearing element may include a plastic material,such as Teflon, nylon, polycarbonate, high-density polyethylene (HDPE),ultra high molecular weight polyethylene (UHMWPE), or the like. Abearing or sleeve can have a cylindrical or tubular shape. For example,a bearing can present a cylindrical shape, having a diameter with arange from about 0.04 inches to about 0.12 inches. FIG. 10 illustrates asnaring system 1000 which includes two bearings or sleeves 1019 a, 1019b disposed about an elongate element 1010. As shown here, bearing orsleeve 1019 a may define, for example by way of an internal lumen, acentral longitudinal axis 1019 ai, and bearing or sleeve 1019 b maydefine, for example by way of an internal lumen, a central longitudinalaxis 1019 bi. Axis 1019 ai may be angularly offset from axis 1019 bi.FIG. 11 illustrates a snaring system 1100 which includes three bearingsor sleeves 1119 a, 1119 b, 1119 c disposed about an elongate element1110. One or more of the bearings may present a spherical shape. Forexample, bearing 1119 b can present a spherical shape having a diameterwithin a range from about 0.04 inches to about 0.10 inches. Snaringsystems having roller bearings or sleeves can allow a physician to applysignificant pulling forces to the catheter, while still maintaining anoperable engagement between the snaring system and the pacing lead. Theroller bearing or sleeve can act to dissipate a portion of the appliedforce, such that a reduced amount of force is applied to the pacing leaditself.

As depicted in FIG. 8, elongate element 810 can have a radiused bottomor distal looped portion. Relatedly, as depicted in FIG. 9, elongateelement 910 can have a straight bottom or distal looped portion. Asshown in FIG. 10, elongate element 1010 can have an angled bottom ordistal looped portion, such that a first straight section is angularlyoffset from a second straight section by about 90 degrees. Accordingly,the snaring system, which presents two roller bearings 1019 a, 1019 bthat can simultaneously contact a pacing lead, provides roller bearingsedges that are angularly offset from one another by about 90 degrees. Asshown in FIG. 11, elongate element Ill 0 can have an angled bottom ordistal looped portion, such that a first straight section is angularlyoffset from a second straight section by about 90 degrees. Accordingly,the snaring system, which presents three roller bearings 1119 a, 1119 b,1119 c that can simultaneously contact a pacing lead, providescylindrical roller bearings edges that are angularly offset from oneanother by about 90 degrees. Typically, the bottom or distal loopedportions are appropriately sized to accommodate a pacing lead. Forexample, as shown in FIG. 8, in some cases a bottom or distal loopedportion may have a length L that is about twice as long as a width W. Toaccommodate a large defibrillator lead having a diameter of about 0.170inches, for example, the looped or hooked portion 815 may have a lengthL of about 0.5 inches and a width W of about 0.2 inches. In some cases,the incorporation of an increased number of rollers or bearings, forexample as depicted in FIG. 11, allows the operator to pull the snaringsystem along a pacing lead using a correspondingly reduced amount offorce.

Snaring systems which include a roller bearing or sleeve as describedherein are well suited for loosely engaging and maneuvering a pacinglead without subjecting the pacing lead to significant pulling forces.Such systems are particularly useful in pacing lead removal methods suchas those described herein with reference to FIGS. 7A and 7B. Forexample, in some cases, it may be desirable or beneficial for thephysician to administer a pulling action, wherein the pacing lead is notfirmly grasped by the snaring system, but instead is more looselyengaged by the snaring system, such that he snaring system allowsmovement of the pacing lead through a snaring loop of the system as thesystem is navigated or manipulated by the physician.

Hence, snare systems can include a closed hook and tag end which can beused to grab a pacing lead or otherwise allow the pacing lead entry intothe hook. An elongate element or wire may include a medical grade wireconstructed of stainless steel, Nitinol, or the like. The elongateelement or wire can be tapered from a larger diameter on a proximalportion or end to smaller diameter on a distal portion or end, and mayhave varying diameters along the length of the wire to add flexibilityor strength where needed or desired. The construction can also include acentral core mandrel, which may also be tapered or of varying diameter,which in tum is covered with a coil. A tag end may present an atraumaticconfiguration. In some cases, a tag end may terminate in a ball end. Insome cases, a tag end may terminate in a pig tail configuration or aflexible coil. Atraumatic configurations can help to prevent or inhibitperforation of the vasculature.

FIG. 11A illustrates side view of a snaring system 1100 a according toembodiments of the present invention. As shown here, snaring system 1100a includes an elongate element or wire 1100 a having a proximal portion1112 a and a distal portion 1114 a. System 1100 a can include a pin viceor handle (not shown) coupled with proximal portion 1114 a of elongateelement 1100 a. As shown here, distal portion 1114 a of elongate element1100 a includes a looped or hooked portion 1115 a. Distal portion 1114 acan also include a tag end 1116 a. According to some embodiments,elongate element 1100 a includes a stainless steel wire having adiameter of about 0.020 inches. Looped portion 1115 a can have a firstlength L1 of about 0.41 inches and a second length L2 of about 0.19inches. As shown here, tag end 1116 a extends from a central portion1113 a of elongate element 1100 a to a distance ET of about 0.22 inches.Snaring system 1100 a includes three bearings or sleeves 1120 a, 1120 b,1120 c disposed about an elongate element 1100 a. Snaring system 1100 aalso includes a distal bead or spherical mechanism 1130 a disposed on adistal portion of elongate element 1110 a.

Bearing 1120 a presents a cylindrical or barrel shape having a diameterwithin a range from about 0.04 inches to about 0.10 inches. Optionally,bearing 1120 a can have a diameter of about 0.07 inches. In some cases,bearing 1120 a can have a length of about 0.12 inches. As shown here, anend portion of bearing 1120 a presents a radius of curvature of about0.2 inches. Bearing 1120 b presents a spherical or oblate shape having adiameter within a range from about 0.04 inches to about 0.10 inches.Optionally, bearing 1120 b can have a diameter of about 0.07 inches. Insome cases, bearing 1120 b can have a length of about 0.06 inches.Bearing 1120 c presents a cylindrical or barrel shape having a diameterwithin a range from about 0.04 inches to about 0.10 inches. Optionally,bearing 1120 c can have a diameter of about 0.07 inches. In some cases,bearing 1120 c can have a length of about 0.19 inches. As shown in FIG.11A, elongate element 1100 a can have an angled bottom or distal loopedportion, such that a first section 1151 a is angularly offset from asecond section 1152 a. In tum, second section 1152 a is angularly offsetfrom a third section 1153 a, which is angularly offset from a fourthsection 1154 a. Further, fourth section 1154 a is angularly offset froma fifth section 1155 a, which is angularly offset from a sixth section1156 a. As shown here, fourth section 1154 a and fifth section 1155 a ofelongate element 1110 a define an angle of about 157.4 degrees, andfifth section 1155 a and sixth section 1156 a of elongate element 1110 adefine an angle of about 130 degrees. Distal bead or spherical mechanism1130 a can present a radius of curvature of about 0.03 inches.Typically, the bottom or distal looped portions of the elongate element,optionally in combination with the bearings, are appropriately sized orconfigured to accommodate a pacing lead.

FIG. 11B illustrates a perspective view of a snaring system 1100 baccording to embodiments of the present invention. As shown here,snaring system 1100 b includes an elongate element or wire 1110 b havinga proximal portion 1112 b and a distal portion 1114 b. System 1100 b caninclude a pin vice or handle (not shown) coupled with proximal portion1114 b of elongate element 1110 b. As shown here, distal portion 1114 bof elongate element 1110 b includes a looped or hooked portion 1115 b.Distal portion 1114 b can also include a tag end 1116 b. According tosome embodiments, elongate element 1110 b includes a stainless steelwire having a diameter of about 0.020 inches. Elongate element 1110 band looped portion 1115 b can present geometrical configurations similarto those described above with reference to FIG. 11A. Snaring system 1100b includes three bearings or sleeves 1121 a, 1121 b, 1121 c disposedabout an elongate element 1110 b. Snaring system 1110 b also includes adistal bead or spherical mechanism 1130 b disposed on a distal portionof elongate element 1110 b. The bearings and bead mechanisms can presentgeometrical configurations similar to those described above withreference to FIG. 11A.

FIG. 11C illustrates a top view of a snaring system 1100 c according toembodiments of the present invention. As shown here, snaring system 1100c includes an elongate element or wire 1110 c having a proximal portion1112 c and a distal portion 1114 c. System 1100 c can include a pin viceor handle (not shown) coupled with proximal portion 1114 c of elongateelement 1110 c. As shown here, distal portion 1114 c of elongate element1110 c includes a looped or hooked portion 1115 c. Distal portion 1114 ccan also include a tag end 1116 c. According to some embodiments,elongate element 1110 c includes a stainless steel wire having adiameter of about 0.019 inches. Elongate element 1110 c and loopedportion 1115 c can present geometrical configurations similar to thosedescribed above with reference to FIG. 11A. Snaring system 1100 cincludes three bearings or sleeves 1122 a, 1122 b, 1122 c disposed aboutan elongate element 1110 c. Snaring system 1100 c also includes a distalbead or spherical mechanism 1130 c disposed on a distal portion ofelongate element 1110 c. The bearings and bead mechanisms can presentgeometrical configurations similar to those described above withreference to FIG. 11A. As shown here, tag end 1116 c can be offset froma central portion 1113 c of elongate element 1110 c at an angle of about5 degrees.

According to some embodiments, a hook can be radiopaque, for example byeither being constructed of a base material having a suitable thickness,or by incorporating radiopaque material. In some cases, a hook orelongate element can contain radiopaque marker bands placed atappropriate or desired locations along the element. In some cases, ahook or coil can include a radiopaque metal such as Pt, Au, Ir,Tungsten, or the like. As noted, snaring systems can also include a hookor elongate element in conjunction with one or more bearing surfaces. Abearing or sleeve can include a low friction material such as Teflon,PE, nylon, or the like, optionally in a tubular or sheath configuration.The bearing or sleeve can be disposed or placed over the wire orelongate element. Optionally, a bearing or sleeve can be placed orpositioned over a hard metal or plastic component mounted on the wire orelongate element, and can be designed or configured to rotate when apacing lead is pulled out of the body with the snare system.

According to some embodiments, a snare system can include an outerjacket, such as a plastic sheath. FIG. 12A illustrates aspects of asnaring system 1200 according to embodiments of the present invention.Snaring system 1200 includes an outer jacket or sheath 1210 and acapture mechanism or elongate element 1220. An operator can position thesnaring system so as to capture a portion of a pacing lead 1250 with ahook tag end 1226 of the elongate element. As shown in FIG. 12B, anoperator can maneuver the snaring system, for example by pulling androtating the elongate element, so as to enclose pacing lead 1250 withina distal loop 1225 of the elongate element. As shown in FIG. 12C, anoperator can maneuver the snaring system, for example by advancing ortranslating sheath 1210 relative to elongate element 1220, so as tobring distal loop 1225 toward sheath 1210, such that hook tag end 1226is received within the sheath, and pacing lead 1250 is securely graspedby distal loop 1225. In some instances, distal loop 1225 operates tosqueeze or press the pacing lead against a distal end 1212 of sheath1210.

Snaring systems which include a hook tag end as described herein arewell suited for loosely engaging and maneuvering a pacing lead withoutsubjecting the pacing lead to significant pulling forces. Such systemsare particularly useful in pacing lead removal methods such as thosedescribed herein with reference to FIGS. 7A and 7B. For example, in somecases, it may be desirable or beneficial for the physician to administera pulling action, wherein the pacing lead is not firmly grasped by thesnaring system, but instead is more loosely engaged by the snaringsystem, such that he snaring system allows movement of the pacing leadthrough a snaring loop of the system as the system is navigated ormanipulated by the physician.

According to some embodiments, outer jacket or sheath 1210 of thesnaring system can have an inner or central lumen. In some cases, sheath1210 can have an inner diameter of about 0.18 inches and an outerdiameter of about 0.22 inches. Sheath 1210 can have a bevel 1211disposed at distal end 1212. In some cases, sheath 1210 can present a12Fr sheath. In some cases, sheath 1210 can be embodied by an outersheath which is used in conjunction with a laser sheath.

FIG. 13A shows an outer sheath 1300 of a snaring system according toembodiments of the present invention. As shown here, sheath 1300 has alength L of about 32 cm to about 33 cm. Sheath 1300 includes an angleddistal end 1310 that presents an angle a of about 40 degrees to about 45degrees. Both distal end 1310 and proximal end 1320 are beveled orchamfered, to reduce or remove burrs or frays that may be present. Asdepicted in FIG. 13B, sheath 1300 can have an inner diameter ID of about0.176 inches, and an outer diameter OD of about 0.2205 inches.

Experimental Results

Selected systems and methods were tested for performing pacing leadextraction via a jugular access site. For a jugular approach, it ispossible to snare the implanted pacing lead and pull a proximal portionof the pacing lead up through the right jugular vein. A pacing lead istypically long enough to extend out the neck, and allow placement of alocking stylet. A jugular approach presents a straight anatomic approachto binding sites in the superior vena cava and ventricle areas. It ispossible to free the pacing lead in the subclavian and innominant veinwith a sheath, which can also be used as part of a snaring method toremove the pacing lead via the jugular vein.

A glass venous heart model was fitted with Tygon tubing of approximately1″ diameter, to exceed the model to the jugular and femoral entry sites.Small and medium simulated leads were placed in the model in thesuperior configuration and secured on the distal end by hemostats at theventricular apex.

In an initial trial, a pigtail catheter that was tested with the heartmodel. The pigtail catheter was inserted though the jugular access site,in an attempt to grab the pacing lead from above. This trial was notsuccessful, because the pigtail curve was not strong enough to pull thepacing lead up and through.

FIG. 14A illustrates a snaring system 1400 that was also tested with theheart model. Snaring system 1400 includes an elongate element 1410having a distal end 1420 and a proximal end 1430. System 1400 alsoincludes a pin device 1440 coupled with proximal end 1430 of theelongate element. Distal end 1420 includes a loop 1422 and a tag 1424.The elongate element 1410 includes a stainless steel wire having a 0.020inch diameter. As depicted herein, distal section 1420 includes astraight bend 1421 which allows engagement of tag end 1424 with a pacinglead, for example, when rotating the hook or loop 1422 via rotation ofpin vice 1440. Once tag 1424 is engaged with the pacing lead, a slightpull applied to the snaring system can secure the pacing lead in loop1422. The first attempt using this design was successful in pulling thepacing lead up and out the jugular.

As depicted in FIG. 14B, snaring system 1400 may also include an outersheath 1450. In use, sheath 1450 can be employed to secure loop 1422,for example by receiving the tag within a central lumen or distalopening 1452 of the sheath. In this way, snaring system 1400 can furthercinch or grasp a pacing lead 1460. The tag end may remain covered bysheath 1450 while the snaring system is used to remove or maneuver thepacing lead.

FIG. 15 shows aspects of a snaring system 1500 which provided excellentresults when used in the heart model. The snaring system includes anelongate element 1510 having a distal end 1520 and a proximal end 1530.Distal end 1520 includes a loop 1522 and a tag 1524. Snaring system 1500also includes a sleeve or bearing 1560 disposed toward distal end 1520of elongate element 1510. For example, bearing 1560 can be disposedabout a portion of loop 1522. It was discovered that by using thissystem, the pacing lead could be maneuvered up and out the jugular veinof the in vitro model, using reduced pulling forces. Moreover, theelongate element can conveniently fit within a 12Fr. outer sheath, andcan be used to effectively remove or maneuver a 12Fr. pacing lead. Asshown here, bearing 1560 is disposed toward a distal end, or bottom, ofloop or hook 1522.

FIG. 15A illustrates a side view of a snaring system 1500 a according toembodiments of the present invention. The snaring system includes anelongate element 1510 a having a distal portion 1520 a and a proximalportion 1530 a. Distal portion 1520 a includes a loop 1522 a and a tag1524 a. Snaring system 1500 a also includes a sleeve or bearing 1560 adisposed toward distal portion 1520 a of elongate element 1510 a. Forexample, bearing 1560 a can be disposed about a portion of loop 1522 a.Bearing 1560 a can have a length of about 0.13 inches, and may present aradius of curvature of about 0.2 inches. As shown here, bearing 1560 ais disposed toward a distal end, or bottom, of loop or hook 1522 a.Distal portion 1520 a can also include a tag end 1524 a. According tosome embodiments, elongate element 1510 a includes a stainless steelwire having a diameter of about 0.020 inches. In some cases, tag end1524 a can extend from a central portion 1513 a of elongate element 1510a to a distance of about 0.24 inches. Tag end 1524 a can include adistal curve or bend 1525 a.

As depicted in FIG. 15A, elongate element 1510 a can have an angledbottom or distal looped portion, such that a first section 1551 a isangularly offset and separated from a third section 1553 a by a secondsection 1552 a. In tum, third section 1553 a is angularly offset andseparated from a fifth section 1555 a by a fourth section 1554 a.Further, fifth section 1555 a is angularly offset and separated from aseventh section 1557 a by a sixth section 1556 a. Second section 1552 acan present a radius of curvature of about 0.07 inches, and fifthsection 1555 a can have a length of about 0.34 inches. Relatedly, firstsection 1551 a can be disposed parallel to fifth section 1555 a, suchthat first section 1551 a and fifth section 1555 a are separated by adistance of about 0.18 inches. First section 1551 a and seventh section1557 a can be angularly offset, so as to define an angle of about 129.6degrees. As shown here, rotatable bearing 1560 a can be disposed on asection 1553 a of loop 1522 a, and loop 1522 a can include a section1555 a distal to the section 1553 a, and a section 1551 a proximal tothe section 1553 a. Sections 1551 a and 1555 a can be in substantialparallel alignment. Relatedly, section 1553 a can be in substantialperpendicular alignment with each of the sections 1551 a and 1555 a.

FIG. 15B illustrates a perspective view of a snaring system 1500 baccording to embodiments of the present invention. As shown here,snaring system 1500 b includes an elongate element or wire 1510 b havinga proximal portion 1530 b and a distal portion 1520 b. System 1500 b caninclude a pin vice or handle (not shown) coupled with proximal portion1530 b of elongate element 1510 b. As shown here, distal portion 1520 bof elongate element 1510 b includes a looped or hooked portion 1522 b.Distal portion 1520 b can also include a tag end 1524 b. According tosome embodiments, elongate element 1510 b includes a stainless steelwire having a diameter of about 0.020 inches. Elongate element 1510 band looped portion 1522 b can present geometrical configurations similarto those described above with reference to FIG. 15A. Snaring system 1500b includes a bearing or sleeve 1560 b disposed about elongate element1510 b. Snaring system 1500 b also includes a distal curve or bendmechanism 1525 b disposed on a distal portion of elongate element 1510b. The bearings and bend mechanisms can present geometricalconfigurations similar to those described above with reference to FIG.15A.

FIG. 15C illustrates a bottom view of a snaring system 1500 c accordingto embodiments of the present invention. As shown here, snaring system1500 c includes an elongate element or wire 1510 c having a proximalportion 1530 c and a distal portion 1520 c. System 1500 c can include apin vice or handle (not shown) coupled with proximal portion 1530 c ofelongate element 1510 c. As shown here, distal portion 1520 c ofelongate element 1510 c includes a looped or hooked portion 1522 c.Distal portion 1520 c can also include a tag end 1524 c. According tosome embodiments, elongate element 1510 c includes a stainless steelwire having a diameter of about 0.019 inches. Elongate element 1510 cand looped portion 1552 c can present geometrical configurations similarto those described above with reference to FIG. 15A. Snaring system 1500c includes a bearing or sleeve 1560 c. In some cases, bearing 1560 hasan inner diameter of about 0.02 inches, and an outer diameter of about0.07 inches. Snaring system 1500 c also includes a distal bend or curvemechanism 1525 c disposed on a distal portion of elongate element 1510c. The bearing and bend mechanisms can present geometricalconfigurations similar to those described above with reference to FIG.15A. As shown here, tag end 1524 c can be offset from a central portion1513 c of elongate element 1510 c at an angle of about 5 degrees.

Hence, snaring systems according to embodiments of the present inventionare well suited for use in grasping or maneuvering pacing leads. Suchsystems can be conveniently used in conjunction with a locking styletwhich provides reliable unlocking. Systems may also be used inconjunction with or incorporate introducers placed at an access site.For example, a snaring system can be used with an introducer at ajugular entry site. In some cases, an introducer may include a valve.Snaring systems may be reversible, and thus can be used to easily graspand release a pacing lead. Moreover, snaring systems may include a tagend or other atraumatic feature which provides protection at or near adistal portion of the system, and thus prevents or reduces thelikelihood of damaging a patient tissue.

According to some embodiments, a snare can be inserted into the jugularvein of a patient. The snare can be used to grasp the pacing lead andpush it down into the right atrium. Once the pacing lead is positionedas desired in the right atrium, the snare may be slid down the pacinglead so that it may grasp the pacing lead near the free end. Oncegrasped near its free end, the pacing lead may be pulled out through thejugular vein. In some cases, grasping snare wires can be extended oradvanced through a wall of a catheter body.

While the exemplary embodiments have been described in some detail, byway of example and for clarity of understanding, those of skill in theart will recognize that a variety of modification, adaptations, andchanges may be employed. Hence, the scope of the present inventionshould be limited solely by the appending claims.

What is claimed is:
 1. A snaring system for engaging an object within apatient's body, the system comprising: a sheath having a sidewall, acentral longitudinal axis and a lumen laterally offset from the centrallongitudinal axis; an elongate element extending through at least aportion of the lumen, wherein the elongate element has a proximal endand a distal end, the distal end comprising a loop; a first rotatablebearing disposed along the loop at the distal end of the elongateelement, the first rotatable bearing having a first length; a secondrotatable bearing disposed along the loop at the distal end of theelongate element, the second rotatable bearing having a second length,the second length being less than the first length; and a thirdrotatable bearing disposed along the loop at the distal end of theelongate element, wherein the second rotatable bearing is disposed alongthe loop at the distal end of the elongate element between the firstrotatable bearing and the third rotatable bearing, the third rotatablebearing having a third length, and the third length being greater thanthe second length.
 2. The snaring system of claim 1, wherein the loopterminates at a tag end, the tag end being disposed proximally relativeto the first rotatable bearing, the second rotatable bearing, and thethird rotatable bearing.
 3. The snaring system of claim 2, wherein thelumen of the sheath is configured to receive the tag end.
 4. The snaringsystem of claim 1, wherein the loop comprises a single wire.
 5. Thesnaring system of claim 1, wherein the elongate element comprises amember selected from the group consisting of a flattened portion, asquare cross-section portion, and a rectangular cross-section portion.6. The snaring system of claim 1, further comprising a deflectionmechanism coupled with the sheath and configured to deflect the sheathand the elongate element.
 7. The snaring system of claim 1, wherein thefirst rotatable bearing and the third rotatable bearing each have atubular shape.
 8. The snaring system of claim 7, wherein the secondrotatable bearing has a spherical shape.
 9. The snaring system of claim1, wherein the second rotatable bearing has a spherical shape.
 10. Thesnaring system of claim 1, wherein the first rotatable bearing defines afirst central longitudinal axis and the second rotatable bearing definesa second central longitudinal axis, and wherein the first centrallongitudinal axis is angularly offset from the second centrallongitudinal axis.
 11. The snaring system of claim 10, wherein the thirdrotatable bearing defines a third central longitudinal axis, and whereinthe third central longitudinal axis is angularly offset from the secondcentral longitudinal axis.
 12. A method of engaging an object disposedwithin a patient, the method comprising: inserting a snaring systemthrough an access site of a patient, wherein the snaring systemcomprises: an elongate element having a proximal end and a distal end,the distal end comprising a loop; a sheath having a sidewall, a centrallongitudinal axis and a lumen in the sidewall and laterally offset fromthe central longitudinal axis through which the elongate elementextends; a first rotatable bearing disposed along the loop at the distalend of the elongate element, the first rotatable bearing having a firstlength; a second rotatable bearing disposed along the loop at the distalend of the elongate element, the second rotatable bearing having asecond length, the second length being less than the first length; athird rotatable bearing disposed along the loop at the distal end of theelongate element, wherein the second rotatable bearing is disposed alongthe loop at the distal end of the elongate element between the firstrotatable bearing and the third rotatable bearing, the third rotatablebearing having a third length, and the third length being greater thanthe second length; engaging the object with at least one of the firstrotatable bearing, the second rotatable bearing, and the third rotatablebearing; and withdrawing the snaring system toward the access site, soas to move at least a portion of the object toward the access site. 13.The method of claim 12, wherein engaging the object further comprisessliding the elongate element within the lumen.
 14. The method of claim12, wherein the loop terminates at a tag end, the tag end being disposedproximally relative to the first rotatable bearing, the second rotatablebearing, and the third rotatable bearing, and wherein engaging theobject further comprises moving the tag end into the lumen.
 15. Themethod of claim 12, wherein the first rotatable bearing and the thirdrotatable bearing each have a tubular shape.
 16. The method of claim 15,wherein the second rotatable bearing has a spherical shape.
 17. Themethod of claim 12, wherein the second rotatable bearing has a sphericalshape.
 18. The method of claim 12, wherein the first rotatable bearingdefines a first central longitudinal axis and the second rotatablebearing defines a second central longitudinal axis, and wherein thefirst central longitudinal axis is angularly offset from the secondcentral longitudinal axis.
 19. The method of claim 18, wherein the thirdrotatable bearing defines a third central longitudinal axis, and whereinthe third central longitudinal axis is angularly offset from the secondcentral longitudinal axis.
 20. The method of claim 12, wherein the loopcomprises a single wire.